Abstract: The combustion characteristics of premixed laminar flame for simulated biogas are studied in a constant volume combustion bomb by using high-speed schlieren photography.The components of simulated biogas contain methane and CO₂, the methane content is from 70% to 75%, CO₂ content is from 25% to 30%.The burning speed and combustion pressure of simulated biogas with different components are compared with pure methane.Experimental results show that the burning speed of biogas decreases compared with pure methane because CO₂ restrains flame from spreading, and the combustion process extends with the increase of CO₂ proportion.